Rheumatoid arthritis is a chronic autoimmune disease that causes inflammation by attacking joints or other parts of the body. Rheumatoid arthritis causes a painful swelling of fingers, hands, feet, wrists, ankles, knees and sometimes can affect other organs of the body such as muscle, skin, lungs and eyes. The underlying cause of rheumatoid arthritis remains unclear and has been investigated continuously. To date, known methods for treating or preventing rheumatoid arthritis are not effective and better treatments are needed. Many hormone medications such as steroids have been widely used to treat arthritis. However, because the use of the hormone medications is not a fundamental treatment and can cause several side effects, the treatment is limited. Arthritis, especially rheumatoid arthritis, causes severe pain so that the patient must take anti-inflammatory agents. Aspirine has been widely used to alleviate the pain for a long time. However, the harmful effect of aspirine on stomach makes it difficult to take a sufficient amount of aspirine necessary for the treatment of arthritis continuously.
Drugs currently used for the treatment of arthritis have several limitations including side effects preventing long-term use of the drugs, the absence of anti-inflammatory effect and the lack of efficacy for treating the arthritis that has already occurred. As a solution of this problem, the development of an effective therapeutic agent for arthritis has been constantly needed. Most of currently used medications for treating arthritis have a certain degree of side effect, although it is varied among medications and patients. Especially, because it is necessary to take medications for a long period of time for the treatment of rheumatoid arthritis, it is very important and urgent problem to develop a novel pharmaceutic agent with low side effect.
EC 18 is a monoacetyldiglyceride and has been separated from deer antler. It has been reported that EC-18 increases survivability ratio of animals in sepsis animal model experiment using cecal-ligation-puncture, and shows no toxicity in a GLP (Good Laboratory Practice) toxicity test. However, the effect of the monoacetyldiacylglycerol compounds including EC-18 on rheumatoid arthritis is not known or disclosed in the prior art. Thus the present inventors aimed to find a compound derived from natural products or a novel compound for the treatment of rheumatoid arthritis and found that the monoacetyldiacylglycerol compound inhibits STAT-3, a therapeutic target for rheumatoid arthritis and can be used to prevent or treat rheumatoid arthritis.